Merge branch 'sg' of git://git.kernel.dk/linux-2.6-block

[pandora-kernel.git] / include / linux / scatterlist.h

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index c6136e8..4571231 100644 (file)
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_SCATTERLIST_H
 #define _LINUX_SCATTERLIST_H
 
+#include <asm/types.h>
 #include <asm/scatterlist.h>
 #include <linux/mm.h>
 #include <linux/string.h>
@@ -23,10 +24,39 @@
  *
  */
 
+#define SG_MAGIC       0x87654321
+
+/**
+ * sg_assign_page - Assign a given page to an SG entry
+ * @sg:                    SG entry
+ * @page:          The page
+ *
+ * Description:
+ *   Assign page to sg entry. Also see sg_set_page(), the most commonly used
+ *   variant.
+ *
+ **/
+static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
+{
+       unsigned long page_link = sg->page_link & 0x3;
+
+       /*
+        * In order for the low bit stealing approach to work, pages
+        * must be aligned at a 32-bit boundary as a minimum.
+        */
+       BUG_ON((unsigned long) page & 0x03);
+#ifdef CONFIG_DEBUG_SG
+       BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
+       sg->page_link = page_link | (unsigned long) page;
+}
+
 /**
  * sg_set_page - Set sg entry to point at given page
  * @sg:                 SG entry
  * @page:       The page
+ * @len:        Length of data
+ * @offset:     Offset into page
  *
  * Description:
  *   Use this function to set an sg entry pointing at a page, never assign
@@ -35,11 +65,12 @@
  *   to an sg entry.
  *
  **/
-static inline void sg_set_page(struct scatterlist *sg, struct page *page)
+static inline void sg_set_page(struct scatterlist *sg, struct page *page,
+                              unsigned int len, unsigned int offset)
 {
-       unsigned long page_link = sg->page_link & 0x3;
-
-       sg->page_link = page_link | (unsigned long) page;
+       sg_assign_page(sg, page);
+       sg->offset = offset;
+       sg->length = len;
 }
 
 #define sg_page(sg)    ((struct page *) ((sg)->page_link & ~0x3))
@@ -54,9 +85,7 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page)
 static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
                              unsigned int buflen)
 {
-       sg_set_page(sg, virt_to_page(buf));
-       sg->offset = offset_in_page(buf);
-       sg->length = buflen;
+       sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
 /*
@@ -81,6 +110,9 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
  **/
 static inline struct scatterlist *sg_next(struct scatterlist *sg)
 {
+#ifdef CONFIG_DEBUG_SG
+       BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
        if (sg_is_last(sg))
                return NULL;
 
@@ -123,6 +155,10 @@ static inline struct scatterlist *sg_last(struct scatterlist *sgl,
        for_each_sg(sgl, sg, nents, i)
                ret = sg;
 
+#endif
+#ifdef CONFIG_DEBUG_SG
+       BUG_ON(sgl[0].sg_magic != SG_MAGIC);
+       BUG_ON(!sg_is_last(ret));
 #endif
        return ret;
 }
@@ -180,6 +216,9 @@ static inline void sg_init_one(struct scatterlist *sg, const void *buf,
                               unsigned int buflen)
 {
        memset(sg, 0, sizeof(*sg));
+#ifdef CONFIG_DEBUG_SG
+       sg->sg_magic = SG_MAGIC;
+#endif
        sg_mark_end(sg, 1);
        sg_set_buf(sg, buf, buflen);
 }
@@ -198,6 +237,13 @@ static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
 {
        memset(sgl, 0, sizeof(*sgl) * nents);
        sg_mark_end(sgl, nents);
+#ifdef CONFIG_DEBUG_SG
+       {
+               int i;
+               for (i = 0; i < nents; i++)
+                       sgl[i].sg_magic = SG_MAGIC;
+       }
+#endif
 }
 
 /**
@@ -210,7 +256,7 @@ static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
  *   on the sg page.
  *
  **/
-static inline unsigned long sg_phys(struct scatterlist *sg)
+static inline dma_addr_t sg_phys(struct scatterlist *sg)
 {
        return page_to_phys(sg_page(sg)) + sg->offset;
 }